Now that there is a solution to this electricity problem for the time being, the scale of the electric classroom can be expanded, so that hundreds of people will not have to grab the more than 20 computers.

Since the current role of computers is still mainly focused on teaching, the performance requirements can be reduced. And as a diskless workstation, the system is launched from the server through the network, which basically has little to do with the performance of the computer.

The frequency of computer replacement is very fast, and the performance of some so-called low-end computers is still very good, more than enough for teaching, but the price is very cheap. For Wei Minsheng, who is short of money in reality, mosquito meat is meat no matter how small it is, so Wei Minsheng gave Liu Mengling and them a purchase list to buy 100 low-end computers.

In order to save money, Wei Minsheng did not buy a special server, because there is no need to ensure 365 days a 24-hour application guarantee service, in case of a crash, restart it.

The server is ready to be installed with Windows2003 Standard Edition, which only supports 4G memory, so Wei Minsheng randomly chose a desktop with a higher frequency.

In order to improve the boot and running speed, the system disk uses a SATA3128G SSD. In addition, two 1T SATA3 HDDs are converted into dynamic disks, and a disk soft array is formed by using zoned volumes to improve the read and write speed of the HDD.

After arranging these things, Wei Minsheng felt that he should still go to Wang Shuangming to see the learning situation of the newly recruited students. When I came to the electric classroom, I saw those students who had not been on the computer squatting on the ground in groups of three or five, constantly gesturing with branches on the sand, even Wang Shuangming was no exception.

Wei Minsheng came to Wang Shuangming's side and asked him what happened.

Wang Shuangming said: "Master, today we learned the problem of filling in the number of nine palaces, according to the mantra on the computer 'wear nine shoes one, left three right seven, two four shoulders, six or eight for the foot, five in the center', you can indeed fill in nine numbers into the nine square grid, and each horizontal, vertical, oblique number adds up to 15. However, a student raised a question, if the middle of the nine-square grid is filled with other numbers, how to solve it with this formula. As you can see, everyone is working on this problem and hasn't found a good solution yet. ”

Wei Minsheng asked Wang Shuangming to find a pen and paper, and then called everyone together and said to them: "The problem of filling in the numbers in the nine palaces, the numbers in the formula represent the position of the nine connected numbers in the sequence, and the numbers in the middle of the nine squares are the numbers in the middle of the sequence, so ah, if the middle of the nine-square grid is filled in 6, then this sequence should be 2, 3, 4, 5...... 10, the ninth number 10 on the top, the first number 2 on the bottom, the third number 4 on the left, and the seventh number 8 on the right...... In this way, the horizontal, vertical, and oblique numbers of the nine palaces filled in according to the mantra add up to 18. ”

Wang Shuangming listened to Wei Minsheng's explanation, and suddenly became enlightened, and several of the students also reacted, and they were about to go to the sand to draw a map for verification.

At this time, Wei Minsheng raised his hand to stop everyone's noise, and then said: "Actually, it is not the easiest to use this formula to solve the problem of filling in the numbers in the nine palaces, I also have a formula, a total of nine words 'corner edge, line connection, corner edge'." If you learn how to use this mantra, the speed at which you can solve this nine-house number problem depends only on how fast you write. Do you want to learn? ”

"Yes! Think! ……”

Wei Minsheng asked everyone to form a circle, drew a big nine-square grid with branches in the circle, used the branches as a baton, and said to everyone: "Let's first say the first sentence of this mantra 'corner edge', which means to find a random grid on the side and fill in the first number of the sequence there." Find another corner, this corner has a requirement, that is, it cannot be adjacent to the previous square, and fill in the second number there. Then there is the edge, and the grid of this side cannot be connected to the previous corner, so fill in the third number there. That's what 'edge of the corner' means. Then there is the phrase 'line connected', which means that the fourth, fifth, and sixth numbers are filled in the diagonal line formed by the empty grid to form a line. Since the second number already occupies a corner, there is only one choice for the diagonal line to be empty, and then the first number can be filled in. This third mantra is the same as the first one, except that the first side is filled in next to the previous number, then the remaining corner, and the last side. According to this method, each set of 9 numbers can be filled in eight different results, and the numbers in the horizontal, vertical, and oblique directions of each method are added to the same. ”

Wang Shuangming listened and said: "It sounds quite complicated, I don't feel as intuitive as the previous mantra." ”

Wei Minsheng said: "The previous mantra is about an absolute position, but there is a lack of change, just like the problem you encountered before, but you filled in a number that is not 5 in the middle, you are stumped, if there are two numbers in the nine-square grid, what should you do?" According to the previous formula, you must first determine the sequence of 9 numbers before you can use the formula to locate it. If you turn the direction of the nine houses a little bit, if you don't find the right direction, this mantra is useless. ”

"yes, I'm just now discovering that if the top box is filled with 3, this mantra can't be applied directly. You must turn the box with 3 to the left and use the mantra to locate it. Also I am familiar with the position of the 3, so I know that the 3 should be on the left. If the third number in the sequence is a 9 and it is filled in the top square, I can't directly think of which direction to rotate the 9. "A student who reacts quickly immediately identified the problem.

Wei Minsheng smiled, and then said to everyone: "I think everyone has also discovered this problem, this is the disadvantage of the absolute position, you can't change the direction, and if you change the direction, it's all wrong." My nine-character mantra uses another way of positioning: relative position. I don't know if you have noticed, this nine-character mantra also reflects a kind of continuity, the corners are not adjacent, and the lines are connected but need to be filled next to each other. According to what this student just said, the top box is filled in 9, and according to my formula, there are many ways to fill in. ”

"The first is to take the 9 in the top grid as the first number, and then fill in the order of the formula: bottom left, middle right, lower right, middle, upper left, middle left, top right, and lower middle. So that the result for each line is 39. ”

"The second way is to take the 9 in the top box as the last number, and fill it in backwards in the order of the formula, so that you can fill in two results, one of which is the same as the result of the mantra you learned earlier, and the result of each line is 15."

"The third way is to regard the 9 in the top grid as the second 'edge' in the first sentence of the formula, fill in a matching line along the second formula, then fill in the third formula, and then reverse the front corner to fill in, and the result of each line is 33."

"Didn't I just say that any sequence of equal differences, that is, sequential numbers with equal differences between two adjacent numbers, can be filled in eight different positions with my mantra, and the result is the same. When you are familiar with this method, you can write an infinite number of solutions at your fingertips, so I said earlier that the speed of solving the problem depends only on the speed of your writing. ”

After finishing speaking, Wei Minsheng left the electric classroom, leaving a group of students in contemplation.

PS: This kind of solution to the problem of filling in the number of the nine palaces is an original dream, due to the limitation of space, it will no longer be decomposed of the problem of filling in the number of the nine palaces that have been filled in with multiple numbers, if you are interested, you can experience it yourself. The speed of solving the problem can be used to bluff people.